NEWS NOTES

7 Essential Genes Identified in Successful Racehorses

An international research team identified a critical set of 7 genes linked to successful racehorses.

“This is the first time this set of genes has been linked to the success of racing breeds. Two of the genes were previously identified for performance in Thoroughbreds and Arabians, but the approach we took was to ask what genes were common to all racing breeds and different from non-racing breeds,” said Emmeline Hill, PhD, a professor at the University College Dublin and the lead scientist on the project.

Scientists from Asia, Europe, North America and Ireland compared the genomes of Thoroughbred, Arabian and Mongolian racehorses with horses bred for other sports and leisure and pinpointed a set of genes that play a significant role in muscle, metabolism and neurobiology.

These genes were found to be clearly different in racing horses and were common to all racing breeds compared with those animals from non-racing breeds.

“Since the discovery of the ‘Speed Gene’ in 2009, we have generated genetic data for thousands of Thoroughbreds and horses from other breeds,” said Dr. Hill, who is also the chief science officer at Plusvital, an Irish equine science company, which participated in the study.

“The very large number of horse breeds developed over the last hundreds of years all over the world have been carefully shaped by selective breeding for different traits desired by breeders. This has led to tall horses, small horses, powerful draft horses, useful riding horses and fast racing horses.

“We have discovered a set of genes common to racing horses, but not all horses within a racing breed have the advantageous gene version, so these findings will be useful to identify the most suitable individuals within a breed for racing or for breeding,” she explained.

The research included the collection of hair samples from 100 horses owned by the champion Ajnai Sharga Horse Racing Team at their breeding farm in Khentii province, Mongolia, the birthplace of Genghis Khan.

Using the DNA from these Mongolian racing horses, along with Thoroughbred and racing Arabian horses, the scientists compared the genomes of these breeds with 21 other non-racing breeds, such as Clydesdale, Connemara pony, Hanoverian, Morgan, Norwegian Fjord, Paint, Shetland, Shire and identified 7 essential genes for racing. These genes play a role in muscle, metabolism and neurobiological functions, and appear to be central to the ability to race among horse breeds

Among the top genes was NTM, which functions in brain development and influences learning and memory. This gene was selected during the horse domestication process, and in Thoroughbred racehorses influences whether a horse ever races.

The finding suggests that equine neurological systems were influenced by both natural and artificial selection associated with domestication and may have overlapped with adaptive traits that are required for racing, suggested David MacHugh, PhD, a professor at University College, and co-author of the study.

“Although racing is a multifactorial trait, with management and training having a considerable influence on the success of a racehorse, this study provides good evidence for major-effect genes shaping the racing trait in horse populations,” he said.

The researchers used gene expression data from skeletal muscle from Thoroughbred horses to investigate if the genes they had identified were involved in the muscle response to exercise and training.

“By integrating these two different data sets we finetuned the list of racing genes to those that were most biologically relevant to racing. One of these genes was MYLK2 which is required for muscle contraction. In humans, MYLK2 is associated with exercise-induced muscle damage,” Dr. Hill said.

For more information:

Han H, McGivney BA, Lucy Allen L, et al. Common protein-coding variants influence the racing phenotype in galloping racehorse breeds. Commun Biol. 2022;5(1) DOI: 10.1038/s42003-022-04206-xhttps://www.nature.com/articles/s42003-022-04206-x